South Korea's lawmakers begin voting on the impeachment of President Park Geun-hye

South Koreans are protesting at the National Assembly in Seoul as they urge for the impeachment of President Park Geun-Hye on December 9, 2016.

A vote is underway on a motion in the South Korean parliament to impeach president Park Geun-hye, who may become the country's first democratically elected leader to be ousted from office.

Parliament is expected to vote in favor of impeachment, with support from some members of Park's own conservative Saenuri Party, but the Constitutional Court must decide whether to uphold the motion, a process that could take up to 180 days.

The parliamentary session for the vote began at 3 p.m. Korea time, with the secret balloting process expected to take about one hour.

Analysts said that lawmakers faced heavy pressure to vote for an impeachment.

"The public backlash to this scandal around President Park has been so broad-based, there will be at least some members who probably factor into their decision-making that the public receptivity to a vote not to impeach could potentially be quite harsh," Nicholas Consonery, senior Asia-Pacific director at advisory firm FTI Consulting, told CNBC's "The Rundown" on Friday.

Crowds of protestors were gathered outside the National Assembly building in Seoul on Friday ahead of the vote, with the number of pro-impeachment people vastly outnumbering the few attendees who said they supported the embattled president.

Ko Kwang-yong, a researcher for the minor opposition Justice Party, told CNBC that he expected the impeachment to be approved.

"An unofficial ran the state affairs for President Park. It is clearly an violation of the Constitution. When some 80 percent of Koreans support the idea, I think she will be impeached," he said.

Park is accused of colluding with a friend and a former aide, both of whom have been indicted by prosecutors, to pressure big businesses to donate to two foundations set up to back her policy initiatives.

Park has denied wrongdoing but apologized for carelessness in her ties with the friend, Choi Soon-sil.

The 64-year-old president said this week she would await the court's ruling, signaling that the six-weeks-long political crisis marked by huge Saturday rallies calling for Park's ouster is set to continue.

Parliament introduced the impeachment bill on Thursday and it must be voted on within 24 to 72 hours. The speaker, Chung Sye-kyun, asked for a vote on Friday.

If the motion passes, the Constitutional Court will determine whether parliament followed due process and whether there are sufficient grounds for impeachment, a process that will involve arguments from the two sides in public hearings.

Prime Minister Hwang Kyo-ahn, who holds what is largely a ceremonial role, would assume interim presidential powers while the court deliberates.

The court is considered conservative in its makeup but some of its former judges have said the case against Park is strong and was likely to be approved.

Jonathan Stayton | CNBC

Leader of People who Love our President, Chang Min-Seong, is one of president Park Geun-Hye's supporters. Park's approval is at a low of 5 percent amid an influence-peddling scandal.

Even if Park is impeached, however, it would not resolve political uncertainty in the country which is faced with challenges on both economic and diplomatic fronts.

"The prime minister doesn't have a mandate to do much of anything. He would have very weak support from the governing Saenuri Party but the opposition may refuse to participant in parliamentary activity," said Argentarius Group's North Asia adviser, Hank Morris.

The Bank of Korea will hold emergency meetings to review policy measures that may be taken against any fallout from the vote, a central bank official said.

In 2004, parliament impeached then-President Roh Moo-hyun, suspending his powers for 63 days while the court reviewed the decision and the prime minister oversaw state affairs. The court overturned Roh's impeachment.

The stakes are high for both sides. The leaders of the two main opposition parties said their 159 members would all resign if the impeachment motion failed, taking responsibility for their inability to follow through on the demands of the public.

Park, the daughter of a former military ruler, is under intense pressure to resign immediately. Her approval rating stood at 5 percent in a Gallup Korea poll released on Friday, a slight improvement from a record low 4 percent. The poll also showed 81 percent of respondents supported the impeachment. Gallup Korea, based in Seoul, not affiliated with U.S.-based Gallup.

Recent political developments in South Korea also raises broader question on the style of Park's leadership, said senior research fellow for northeast Asia with the Asia Programme at Chatham House, John Nilsson-Wright.

"When she was a candidate for president, she claimed she would be a president for all Koreans, but she has proven herself to be a president who is seen by Koreans as extremely remote," Nilsson-Wright told CNBC's "Squawk Box."